Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Geology 12 Presents Hand out note helper WS 8.1 Geologic Time A: Fossil Record & Geologic Time Scale B: Relative Dating C: Absolute Dating A: Fossil Record A: Fossil Record & Geologic Time Scale • Paleontology: study of fossils • Taphonomy: preservation of organisms • For fossilization to occur, it requires: – 1. organisms must possess hard parts (shell, bones, teeth) – 2. favourable environmental conditions – rapid burial to prevent physical and biological destruction (soft seds’ for delicate organisms) – 3. large population helps Hard Parts Rapid Burial Large Population • Types of Fossilization (remember WS 6.2) – 1. Body Fossil • a) unaltered – i) soft parts (woolly mammoth) – Preserved in permafrost, amber, tar pits – ii) hard parts (bones, teeth, shell) • b) altered –i) permineralization: material is added to pore spaces (silica) …silicified wood. –ii) replacement: original material is dissolved and replaced by another material molecule by molecule. –iii) recrystalization: mineral recrystalizes into another (shell: aragonite -> calcite) –iv) carbonization: volatiles escape leaving only carbon (plant/leaf) – 2. Trace Fossils • a) track: foot prints 2oma Beaver • b) trails: imprints of bodyburrow parts (dino hide) • c) burrows: made by worm & shrimp in soft sediment before lithification • d) borings: holes made in shells hide or solidDinosaur rock • e) coprolites: feces Footprints of father-son 3.6 myrs ago in volcanic ash -3. Mold/Cast a) Mold: cavity that preserves organism’s 3. Rock split to shape. 1. Shell buried 2. Shell dissolved (void space) reveal mold b) Cast: sediment fills in mold to preserve organism’s shape. 3. 2. Shell 1. Shell dissolved sediment/precipitate buried (void space) deposited in mold) mold 4. Rock split for reveal cast cast mold Mold of Trilobite • The Fossil Record: – Incomplete: not all organisms preserved – Biased towards: • 1. organisms with hard parts • 2. organisms that lived in shallow marine environments (best chance of rapid burial • 3. organisms with large populations Uses of Fossils • 1. Correlation (lateral continuity) ? ? ? ? ? ? Uses of Fossils • 1. Ex A (see note helper WS 8.1 p.3) Fossil X Fossil X Fossil Y Fossil Y Fossil X Fossil Y • Ex B Try to do it without fossils 3000 m 2200 m 1500 m elevation elevation elevation 200 km 230 km 2000 m 1200 m 500 m elevation elevation elevation • Ex B Try to do it without fossils 3000 m Fossil A elevatio Fossil D n Fossil E Fossil B Fossil D elevatio n Fossil G 2000 m elevatio Fossil H Fossil F Fossil G elevatio n Fossil H Fossil F Fossil C 1500 m 2200 m Fossil I 1200 m elevatio n 500 m Fossil J elevation • 2. Paleoenvironments: shallow or deep marine • 2. Paleoenvironments: land, shallow or deep marine • 3. Paleoecology: how organism adapted, related to other organisms. • 3. Paleoecology: how organism adapted, related to other organisms. • 4. Paleogeography: tells distribution of land,seas, paleolatitude, shorelines and land connections. Ex: fern leaf = land/swamp • 5. Paleoclimates: hot, cold, wet, dry – Ex: palms in hot climate. • 6. Evidence of Evolution: change over time in species. • 6. Evidence of Evolution: change over time in species. • 7. Evidence of Plate Tectonics • 7. Evidence of Plate Tectonics • 8. Index Fossils: determine the age of bedrock unit if you time when fossil lived. • What makes a good index fossil: – a) existed for a relatively short period of time – b) widely distributed around the World – c) easily identified – d) readily preserved Most important Fossil D Fossil C Fossil B Fossil A Time • Examples see note helper WS 8.1 p.4 Permian Carboniferous Devonian Silurian Ordovician Cambrian Best index fossil = B Age of rock is silurian Fossil H Fossil G Fossil F Fossil E Time • Examples see note helper WS 8.1 p.4 Quanternary Tertiary Cretaceous Jurassic Triassic Permian Best index fossil = F Age of rock is cretaceous Marine Environments • 1. Benthic = bottom – a) supratidal = above high tide (aver’ sea-level) • (covered only during floods or storms) • One of the toughest environments to exist • Is beach area – b) intertidal = between high and low tides • brackish during rain/super saline during the sun • Another tough place to exist – c) subtidal/sublitoral = low tide to edge of continental shelf • Most life (coral reefs) – d) bathyal = on continental slope • 200 m to 4000m deep – e) abyssal = ocean bottom • 4000 m – f) hadal = down the trench • Down, down, … 11,000 m supratidal High tide intertidal subtidal Low tide • 2. Pelagic = in water column (swim/float) – a) Neritic = above continental shelf – b) Oceanic = above deep ocean basins Life Habits • 1. Planktonic = organisms that float within the water column – Ex. Jelly fish, plankton • 2. Nectonic = animals that swim within the water column – Ex. Fish, dolphins, whales , ammonites • 3. Benthonic = live on bottom – a) infauna – live within the sediment • Ex: worms – b) epifaunal – live on the sediment • i) vagile = vagrant = move about –Ex: lobster, starfish • ii) sessile = stationary –Ex: coral, barnacle, sponge Evolution • Evolution Theory = change over time through natural selection (through variation via mutations, within a species and the struggle to survive, only the “fittest” offspring live to reproduce and pass on their genes. • How fast? – Darwin believed in Phyletic Gradulism (PG): slow, gradual evolution over many generations VS. Punctuated Equilibrium (PE) occurs rapidly over short periods of time followed by long periods of little or no change. PE: Caused by organisms living at the edge of environment under the greatest evolutionary pressure. These organisms undergo the greatest change, and if: i) the environment changes for the worst these organisms will be better prepared for survival than the main body. ii) the organism is re-introduced to the main environment, their superiority could result in extinction of the mother species. Evidence for Evolution • 1. Anatomical: – a) Embryology: close resemblance of embryos under development – b) Homology: (homologous structures): bones of limbs have been modified for different functions through evolution. – c) Vestigial Structures: inherited organs that now serve no purpose • 2. Biological – a) Selective Breeding: man has caused microevolution over the last 10,000 years by breeding plants and animals for certain characteristics • Ex: dog, wheat – b) Ontogenetic changes: evolutionary changes that occur during an organisms life time: • Ex: egg -> catepillar -> pupae -> butterfly • Ex: egg -> tadpole -> frog – c) Biochemistry: similarity between organisms implies common ancestry • Ex amino acids Common amino acids • 3. Paleontological: ample evidence in the fossil record demonstrates evolution Ex: Homo habilus -> Homo erectus -> Homo sapien Patterns of Evolution (4) • Orthogenesis = change in morphology (body structure) over time. • 1. Adaptive Radiation: a species evolves quickly over a short span of time into different species time – Common during times following large extinctions Ex: mammals after dinosaurs morphology Cretaceous extinction • 2. Convergent Evolution: 2 organisms become more alike time – Ex: succulents & cacti, dolphin & penguin morphology • 2. Convergent Evolution: 2 organisms become more alike – Ex: succulents & cacti, dolphin & penguin • 3. Divergent Evolution: 2 similar organisms become more different through time time – Ex: Griz and polar bear morphology • 3. Divergent Evolution: 2 similar organisms become more different through time – Ex: Griz and polar bear • 4. Parallel Evolution: 2 organisms change in the same way. time – Ex: Muskox and Mammoth morphology Hand out Note helper WS 8.1 p.5 time A B C D morphology Which organism(s) are undergoing: 1. the greatest change/morphology: B 2. adaptive radiation: A 3. convergent evolution: B & C 4. divergent evolution: D & E 5. parallel evolution: C & D E Causes of Extinction • 1. Plate Tectonics – a) fast modification of climate • Ex: Megladon (giant shark) vs. American land bridge – b) plates come together introducing non-indigenous species 1 continent 1 continent • 2. magnetic pole reversal and cosmic rays – No magnetic field = more cosmic rays • 3. meteorite/asteroid impact – Permian 245 ma 80% of species extinct – Cretaceous 66 ma 50% species extinct • 4. new predator/parasite/disease Ultimate Predator: Mother Inlaw • 5. volcanism: ash blocks sunlight • 6. supernova nearby radiates life – Ordovician extinction of all life within 10 m of surface – Pos’ cause for Mammoths demise • Do WS 8.2 for HW • Do WS 8.3 in class with DVD video Fossil Notes Part 2 • Presents Geologic Time Scale • A: Earth: the beginning • 1. 4.5 ba = 4,500 ma = Earth forms from molten ball of magma heated by meteorite impact collisions. • 2. Earth: inner-solid outer-molten (no solid crust) – Atmosphere = H2, methane, ammonia, H2S, N2, Ar, water vapour. • 3. Rapid convection currents and magma differentiation occurred (remember Chps 3-4) – a) fractional crystalization (Fe-Mg mins’ ) – b) more silisic rocks have lower melting temperatures -> melted 1st -> rose to surface Molten iron sinking towards core • 4. Convection current drove lighter/more silisic material together (form early continents) while heavier/more mafic material subducts. Mantle • As these small pieces of silisic rock were driven against each other, they formed early continents by continental accretion, later to become cratons. – Largely igneous and gneissic rocks – 4.0 ba oldest still in existence in Greenland Continents collide becoming ever larger as they accrete silisic crust that has formed on the surface of the Earth. • 5. Outgassing of volatiles (mainly water) from molten rock began 4.5 ba and was fairly complete (oceans filled) by 2.0 ba. • B: Life • 1. 3.7 ba = first life appeared: stromatolites, an algae structure (procaryotic = no nucleus) – Single celled organisms that dominated 3.7 ba to 570 ma – Lived in shallow marine (intertidal - subtidal) – Used fermentation initially for energy (like black smokers) stromatolites • 2. 3.0 ba photosynthesis begins with cyanobacteria (other bacterias also form) – Atmosphere converted from CO2 to O2 • 3. 2.5 to 2.0 ba: red beds of iron oxide form as iron oxidizes from free oxygen 2.3 ba: first glaciation period • 4. 2.0 eucaryotes (have nucleus) form – First carbonates (Lst & dolomite) • 5. 2nd glacial period (Ice Planet) Ice is 10 m at equator in ocean! • C: Explosion of Life (570 ma to recent) • Ice age ended and new seas opened up allowing new organisms to spread out and open new niches – (more on evolution in Lab 8.1 and Lab 8.2) “Explosion of Life” • D: Geology of West Coast • Orogeny = mountain building – 320 – 245 ma (Penn’ –Permian): Appalachian Orogeny in eastern US – 208 – 66 ma (Jurrasic – Cretaceous): BC Terranes (islands like Japan, New Zealand) accrete onto Alberta. – 70 - 45 ma (Cretaceous – Eocene) Laramide Orogeny (Rocky Mtns’) Appalachian Orogeny 320-245 ma – 144 – 37 ma (Cret’ – Eocene): major magmatism in BC (Hydrothermal ores!) – 37 – 24 ma (Oligocene) : Columbia Plateau (Builds up 2500m thick!) – 24 – 5 ma (Miocene): volcanism: Yellowstone Park begins – 6 ma (Pliocene) Grand Canyon starts to cut – 2 ma to recent (Pleistocene) Cascade/Skagit Mtns’ and Cascade Range (volcanoes) forms – 1.4 ma (Pleistocene): period of continental glaciation (3rd in Earth’s history) (4 N Am. Ice periods) Coast Range of BC (+ Sierra Nevada) 144 – 37 ma Columbia Basalt Flood 37 – 24 ma Yellowstone Hotspot 24 – 5 ma Grand Canyon began 6 ma Skagit Mountains 2 ma to recent 4th Ice Advance during last 1.4 ma (Pleistocene Glaciation) Geologic History • = subdivisions of the Earth’s history by: • 1. appearance and disappearance of particular fossils (index) – Ex: Phanerozoic= time that all life has existed – Paleozoic = ancient life 570 – 245 ma – Mesozoic = intermediate life 245 – 66 ma – Age of reptiles & conifers – Cenozoic = recent life 66 ma to now – Age of mammals & flowers • 2. Location of certain rock sections – Ex: Cambrian = Wales – Ex: Jurassic = Jura Mtns’ in France – Ex: Devonian = Devonshire in England • 3. Type of Rock – Ex: Cretaceous = creta = chalk – Ex: Carboniferous = coal • Do Lab 8.1 Geologic History • Do Lab 8.2 Fossil ID • Do WS 8.4 Geologic History